It has been recently determined that there are many situations when stored, donated blood, as well as other types of blood and blood components, should be filtered to remove microemboli of aggregated blood elements and the like, prior to administration to a patient. In paticular, older, stored blood which is nearing its expiration date has been found to be greatly improved by filtering, to prevent the microemboli from lodging in the lungs, brain, and elsewhere, thus avoiding various degrees and types of injury to the patient.
A considerable number of blood filters are now commercially available for use with stored, whole blood, or for reprocessing fresh blood in heart-lung machines, as well as blood which has passed through a cardiotomy sucker.
In a blood filter it is, of course, desirable that the filter remove as many particles as possible which are larger than red cells (which have an average size of 7 microns), while at the same time exhibiting a rapid flow rate of blood through the filter, and a high capacity to process several units of blood. Accordingly, the filter does not have to be replaced excessively often as a patient is receiving a large amount of blood.
Furthermore, a filter should be susceptible to automated commercial production techniques, so as not to be excessively expensive. It must also be reliably leakfree. Also, it must be free of shunt passages which permit blood to pass around the filter element without filtering action.
The filter of this application exhibits excellent high-flow characteristics. At the same time it provides surprisingly excellent levels of particle removal from blood. Furthermore, it is susceptible to reliable, automated sealing against blood shunting and to sterile sealing of the contents from the exterior, on a low-cost basis.